itp: The Interpolate, Truncate, Project (ITP) Root-Finding Algorithm version 1.2.1

itp 1.2.1

Bug fixes and minor improvements

• The issue described at RcppCore/Rcpp#1287 has been fixed to avoid WARNINGs from CRAN checks on some platforms. Thank you to Dirk Eddelbuettel for providing the fix so quickly!